We readdress the well-known nephelauxetic effect in coordination compounds of transition metal ions and analyze its possible origins presented in the literature. The initial hypothesis was to ascribe the reduction of the effective Racah parameters B and C of the electron–electron interaction in the complexes as compared to their respective free ion values (which is the essence of the nephelauxe...

The photoexcited triplet states of a series of linear and cyclic butadiyne-linked porphyrin oligomers were investigated by transient Electron Paramagnetic Resonance (EPR) and Electron Nuclear DOuble Resonance (ENDOR). The spatial delocalization of the triplet state wave function in systems with different numbers of porphyrin units and different geometries was analyzed in terms of zero-field spl...

We present a novel design of a micro-structured large-pitch, large-mode-area (LMA) asymmetric rod-type fiber. By reducing the cladding symmetry through six high-refractive index germanium-doped silica inclusions, the fiber features strong higher-order mode (HOM) delocalization, leading to a potentially enhanced preferential gain for the fundamental mode in active fibers. In addition, high resol...

A mechanism to reduce radiation loss from integrated optical cavities without a complete photonic bandgap is introduced and demonstrated. It is applicable to any device with a patterned substrate (including both low and high index-contrast systems), when it supports discrete guided or leaky modes through which power escaping the cavity can be channeled into radiation. One then achieves the asso...